Aluminum flake pigments have potential to be used in a variety of applications such as coatings and cosmetics, among others. Aluminum pigments are advantageous as they give coated objects a silvery metallic sheen, have a light to dark color travel, have good sparkle, excellent hiding power and are extremely light and weather fast. Moreover, by blending with different organic or inorganic pigments, different colors with a metallic effect can be achieved.
However, blending traditional organic pigments with aluminum has some drawbacks. Most importantly, some of the metallic character is lost due to increased scattering by the organic pigment particles. Having a colored aluminum pigment where the flake is colored would be advantageous as the metallic character can be preserved. Unfortunately, many of the strategies used to color aluminum are laborious, requiring complicated and/or dangerous procedures and potentially toxic precursors. Other strategies used to color aluminum, such as direct attachment of a pigment to the aluminum surface, suffer from a number of drawbacks, including an inability to achieve deep colors, poor adhesion of the pigments to the aluminum surface, and a reduction of lightfastness of organic pigments on the aluminum surface. The last of these issues is caused by the fact that organic pigments are essentially exposed to more light; the incoming light and the light reflected by the surface of the aluminum.